@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.Main_Activity);
    this.setTitle("Title name");
}

MainActivity内部:

public class act1 extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.act1);

    setTitle("First Activity");

}

}

代码帮助我更改了标题。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_name);
    ActivityName.this.setTitle("Your Activity Title");}

setTitle(“应用程序”); 在MainActivity.java中更简单 我会说。

试试setTitle本身，像这样:

setTitle("Hello StackOverflow");

如果你正在使用onCreateOptionsMenu，你也可以在onCreateOptionsMenu中添加setTitle代码。

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu, menu);

    setTitle("Neue Aktivität");
    return true;
}